In our studies of motivation, we have found that monkeys work faster and with fewer errors when a cue indicates that a juice reward will be delivered immediately after the next correct response than when the cue indicates that additional trials will be needed. Single neuronal responses in the ventral striatum are directly related to the associatively learned meaning of the cue in this complex behavioral task. Specifically, these neurons keep track of whether the animal is at the beginning of or somewhere in the course of a behavioral sequence that ultimately leads to reward. Some neurons signal that anew series of trials is starting , other neurons signal that a series of trials is in progress, and still others signal the rewarded trial is starting when it follows one or more unrewarded trials. Thus this population provides a neural signals that could reinforce complex reward-seeking behavior. Because of its close connections with the visual system, the perirhinal cortex was thought to be and has been shown to be implicated in important for pattern recognition behavior. Perirhinal cortex and ventral striatum are strongly connected, and both show highly structured organization of dopaminergic input leading us to speculate that perirhinal cortex might show reward-related activity similar to the activity we had seen in the ventral striatum. Therefore we recorded neurons in the perirhinal cortex during a variant of the multiple reward-schedule task described above. We have found that a large proportion of neurons in perirhinal cortex (~50%) show associatively learned activity similar to that seen in the ventral striatum. In contrast, neurons located just 3-4mm away in area TE of the temporal cortex, a high level visual area, fail to show this reinforcement- related effect. We compared this associatively learned reinforcement activity to neuronal responses related to the direct memory of stimulus identity. Both TE and perirhinal neurons show stimulus selectivity in the responses during a short term memory task, as has been reported frequently in both brain regions. It appears that perirhinal is the first place in visual processing where signals related to motivation and reward are combined with signals related to stimulus identity. Given the emphasis on the relation between perirhinal cortex and pattern-recognition behavior in the past, the prominence of the perirhinal activity related to the reward schedules was unexpected. To investigate whether perirhinal cortex plays a critical role in this associately learned reward schedule related behavior, we tested both normal monkeys and monkeys with bilateral rhinal cortex lesions in the reward schedule task described above. We found that normal monkeys associate new visual cues with the schedule starting within a single training session. However, animals with bilateral rhinal cortex ablations only begin make this association after four weeks of daily training. Thus, perirhinal cortex is a critical structure for developing the associative relation between a visual cue and its meaning for reward schedules. We hypothesizet hat dopaminergic input provides signals sensitive to long-termp rogress through a planned or expected series of tasks which culminated in reward. - motivation, reinforcement, learning, memory, dopamine, ventral striatum, rhinal cortex, single neurons